Implantable medical devices, such as electrical stimulators may be used in different therapeutic applications, such as deep brain stimulation (DBS) or. A medical device may be used to deliver therapy to a patient to treat a variety of symptoms or patient conditions such as chronic pain, tremor, Alzheimer's disease, Parkinson's disease, other types of movement disorders, seizure disorders (e.g., epilepsy), obesity or mood disorders. In some therapy systems, an external or implantable electrical stimulator delivers electrical therapy to a tissue site within a patient with the aid of one or more implanted electrodes, which may be deployed by medical leads or on a housing of the stimulator.